Improved gasoline fuel components



United States Patent IIVIPROVED GASOLINE FUEL COMPONENTS Fredrick L.Jonach, Kew Gardens, N.Y., assignor to Esso Research and EngineeringCompany, a corporation of Delaware Filed Jan. 2, 1958, Ser. No. 706,564

8 Claims. (Cl. 208-16) No Drawing.

The present invention concerns the treatment of naphtha fractions thatare ordinarily not suitable as components of gasolines for modernautomotive engines to render them acceptable for that use. The inventionis particularly directed to a process for improving the enginecleanliness characteristics of such naphtha fractions when they are usedin motor gasolines as well as to the improved naphtha fractionsthemselves.

lead and tetra ethyl lead are valuable gasoline constit-v uents in thatthey reduce engine knocking that is attributable to compression ignitionphenomena, they are at the same time detrimental in that they cause theformation of engine deposits which in the long run will increase theoctane level requirements and give unsatisfactory engine operation.These deposits become incandescent during engine operation and ignitethe mixture of fuel and air prematurely by a phenomenon commonlyreferred to as surface ignition. The deposits also build up on thepoints and insulators of spark plugs and thus cause spark plugmisfiring. Such deposit buildups are customarily avoided or minimized byemploying scavenger agents. The most commonly used agents are ethylenedichloride and ethylene dibromide which, during combustion, furnishhalogen acids that combine with the lead and convert it to a relativelyvolatile lead halide which is removed with the gasoline engine exhaustgases. 'Ihese scavenger agents are not entirely satisfactory, however,and deposit formation and the resulting difficulties occur in modernhigh compression engines in spite of the use of these scavenger agents.

It has been found more recently that organic compounds of phosphorus aredesirable additives for inclusion in leaded gasolines in that they areeffective for overcoming the difliculties that are associated with theuse of conventional lead scavenging agents. It is'one function of thepresent invention to introduce minor proportions of phosphorus compoundsinto the motor fuel for the purpose stated. It is another function ofthis invention to convert cracked naphtha fractions that are normallyunsuitable as gasoline components into fractions than can be used toadvantage in gasoline compositions.

In accordance with the present invention petroleum.

cracked naphthas, particularly the higher boiling fractions of heavythermal reformates, are treated with the reaction products of phosphorussulfides and olefin polymers, thereby removing from those fractions theimpurities that normally cause engine fouling when gasolines containingthe cracked naphthas are used in an internal combustion engine. At thesame time the treat- 2,985,578 Patented .May 23, 1961 "ice ment of thecracked naphtha fractions in this manner about 1,000 to 5,000 molecularweight.

pounds that are useful in assisting in the scavenging of lead fromleaded gasolines burned in the engines.

The reaction products employed in the present invention for treating thecracked naphtha fractions are obtained by reaction of a sulfide ofphosphorus, preferably P S with a C to C olefin polymer, i.e., ofethylene, propylene, butylene or isobutylene, of from about 250 to about10,000 molecular weight, and preferably Isobutylene polymers arepreferred. The reaction product is readily obtained by a reaction of thephosphorus sulfide with the olefin polymer at a temperature of about 200to 600 F. and preferably from about 300 to about 500 F. Preferably, fromabout 2 to about 5 molecular proportions of the olefin polymer areemployed for each molecular proportion of the phosphorus sulfide in thereaction. It is ordinarily desirable to employ an amount of thephosphorus sulfide that will react completely with the olefin polymer.The reaction is continued until substantially all of the phosphorussulfide has been reacted.

The phosphorus sulfide-olefin polymer reaction product is then employedto treat a cracked naphtha fraction. The amount of phosphorus sulfidereaction product used will be in the range of from about V of the weightof the naphtha fraction treated to about an equal weight based on thenaphtha fraction and preferably about ,4 to /s of the weight of thelatter. Treating temperatures will range from about to about 350 F. andpreferably from about 180 to about 250 F. The reaction is continued fora period of from /2 to 10 hours and the reaction product is thendistilled to recover the treated naphtha as the distillation product.Although almost any normally undesirable cracked gasoline fraction maybe treated by the process of the present invention, it is particularlyadaptable to the treatment of heavy reformate fractions, from the wellknown petroleum refining processes of reforming and hydroforming, andespecially to the treatment of what are known as heavy thermal reformatefractions, i.e., the fractions boiling above 200 F. and below 550 F.,e.g., between 250 F. and 450 F.-

The following examples are illustrative of the invention.

EXAMPLE 1 A quantity of isobutylene polymer of 1100 Staudinger,

molecular weight was heated with 10 percent by Weight of P 5 at about425 F. for about four hours. The material was then diluted with aquantity of a light hydrocarbon oil to about 60 percent concentrationfor ease in filtration and further handling. The filtered concentrateanalyzed 2.63 percent sulfur and 1.42 percent phosphorus.

EXAMPLE 2 head temperature of 292 F. at 150 mm. Hg and then The treatedreformate was recovered asthe distillate. The optical density of therecovered product was measured as an indication to 270 F. at 10 mm. Hgpressure.

of the improvement obtained by the treatment. The results are given inTable I for the materials untreated or raw, and washed with a 20%aqueous solution of caustic soda, i.e., NaOH Washed.

Optical density is measured in terms of the logarithm of (IOU/percentlight transmitted). It is well known in the art that the enginecleanliness characteristics of cracked orreformed petroleum naphthas canbe evaluated by a comparison of the optical densities of the naphthasafter treatment with suitable reagents such as fluoboric acid, sulfuricacid etc. The values of optical density in Table I above and TableIII'below were obtained by measuring light transmission in a Lumetroncolorimeter after the samples of naphtha had been treated as follows:Treat 1 cc. of sample with cc. of reagent consisting of 10 parts ofdilute sulfuric acid and 90 parts of acetic acid; then dilute to 100 cc.with acetic acid, and measure optical density.

By actual tests of various gasolines in a Chevrolet engine, it wasestablished that the optical density measured the relative quantities ofdeposits in the engine as shown in Table II wherein the sludge rating of100 was obtained on a commercial motor gasoline of regular grade andaverage cleanliness quality.

1 Test procedure Eli-4'45 described by l). '1. Rogers, W. W. Rice and F.L. Jonach before meeting of Society of Automotive Engineers, November10, 1955. Test consumes 6 hours in 3 cycles of about 2 hours each'at' 40B.H.P. output. First cycle 500 r.p.m., water jacket and oiltemperatures115 F.; second cycle 2000 r.p.m., Water jacket temperature 160 F.,

oil temperature 175 F.; third cycle 2000 r.p.n1., water jackettemperature 160 F., oil temperature 225 F. Total test duration, 110 hrs.

EXAMPLE 3 In the same manner as in Example 2, various fractions.

of the thermal reformate were individually treated with the reactionproduct of Example 1. The optical density measurements of the treatedproducts and the optical densities of the corresponding untreated cutsare given in Table III. The data in Tables I and III indicate that thevarious: thermal reformate cuts were considerably improved by theprocess of the present invention.

Table III (Optical Density) X100 Untreated Treated Thermal Reiormate Cut1 .Q.- 66. 8 1. 4 Thermal Reformate Cut 92.1 2. 8 Thermal Reformate Cuta 188. 6 6. 9

1 Boiling range 400416 F. Boiling range Ado-427 F. 3 Boiling range 427F.+

' to 10 hours with from% its weight toan equal weight 4 Each of thetreated fractions was found on analysis to contain phosphorus as shownin Table IV.

For lead scavenging purposes, the phosphorus content of gasoline iscontrolled between 0.05 and 1.0 theory, or stoichiometric proportion, ofthe lead. If 3 cc. of tetraethyl lead, i.e., 5 grams, is added to onegallon of gasoline, which weighs 3000 grams, the lead content of thegasoline will be about 0.1 percent, since the lead content of tetraethyllead is 64 percent. One theory of phosphorus is equal to about 10percent of the Weight of lead. One theory of phosphorus in a gasolinecontaining 0.1 percent lead would amount to about 0.01% by weight of thegasoline. Thus, the treated reformate analyzing 0.0005% phosphoruscontained 0.05 theory of phosphorus when the reformate wasleaded with 3'cc.

' of tetraethyl lead per gallon.

This invention is not to be limited to the specific examples hereinpresented for the purpose of illustrating the invention as modificationsthereof within the skill of the art are contemplated. The scope of theinvention is limited only by the claims appended hereto.

What is claimed is: L

1. An improved cracked naphtha component for a gasoline composition towhich an alkyl lead antiknock agent is to be added, which improvednaphtha component is obtained by treating a cracked naphtha fraction,containing materials that normally tend to cause engine fouling whenemployed as a component ofan internal combustion engine fuel, at from to350 F; for from to 10 hours with from itsweight to an equal weight ofthe reaction product of. a sulfide of phosphoruswith a C to C olefinpolymer of from. 250'to 10,000'

in said cracked naphtha fraction comprises a thermal reformate fractionboiling inthe range-of 2.0.0 to 550 F.

4. A naphtha component'as defined by claim 1 wherein said reaction withsaid sulfide of phosphorus is,conducted at temperaturesin the rangeH'ofabout. 200 to 5. The method of improving a cracked, naphtha frac-- tioncontaining materials that. normallyftendtocause engine fouling whensaid' crackednaphtha fraction; is. employed as a component of an,internal combustion.

engine fuel, which method comprises treating said naphtha fraction atfrom, 150 to 350 for from of the reaction product ofa sulfide ofphosphorus with a C to C olefin polymer of from 250 :to 10,000zmolecularweight, distillingv the naphtha materialthus obtained and recovering thetreated naphtha fraction; as adistill ate;

6. A method as defined in. claim; 5v wherein. said .re-

action of. said.sulfidesofiphosphorus with;:said:.olefin. poly-References Cited in the file of this patent UNITED STATES PATENTS Hillet a1 July 5, 1955 Bartleson June 4, 1957 Bartleson June 4, 1957 Brehmet a1. July 28, 1959

1. AN IMPROVED CRACKED NAPHTHA COMPONENT FOR A GASOLINE COMPOSITION TOWHICH AN ALKYL LEAD ANTIKNOCK AGENT IS TO BE ADDED, WHICH IMPROVEDNAPHTHA COMPONENT IS OBTAINED BY TREATING A CRACKED NAPHTHA FRACTION,CONTAINING MATERIALS THAT NORMALLY TEND TO CAUSE ENGINE FOULING WHENEMPLOYED AS A COMPONENT OF AN INTERNAL COMBUSTION ENGINE FUEL, AT FROM150 TO 350*F. FOR FROM 1/2 TO 10 HOURS WITH FROM 1/50 ITS WEIGHT TO ANEQUAL WEIGHT OF THE REACTION PRODUCT OF A SULFIDE OF PHOSPHORUS WITH AC2 TO C4 OLEFIN POLYMER OF FROM 250 TO 10,000 MOLECULAR WEIGHT,DISTILLING THE NAPHTHA MATERIAL THUS OBTAINED, AND RECOVERING THETREATED IMPROVED NAPHTHA FRACTION AS THE NAPHTHA DISTILLATE.